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Alternatives to Lead as a Machinability Enhancer in Free Cutting Steels
Author(s) -
Reynolds Philip,
Block Volker,
Essel Ingo,
Klocke Fritz
Publication year - 2007
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.200706305
Subject(s) - machinability , metallurgy , materials science , lubricant , machining , high speed steel , composite material
Low levels of lead are added to free cutting steels to improve machinability. For environmental reasons, there is interest in alternatives to lead that are technically and commercially viable. The machining performance of eight low carbon free cutting steels with alternative machinability enhancers, including additions of bismuth, increased sulphur (with and without tellurium), tin and phosphorus, has been investigated. In tests with high speed steel tools and lubricant, the leaded steel showed the best performance in terms of production rate, surface finish and chip form. In tests with coated carbide tools at a range of cutting speeds the standard non‐leaded 11 SMn30 steel performed well in terms of tool wear, but showed poorer chip form than the leaded steel. The steels with increased sulphur showed improved performance compared with the 11SMn30 steel in tests using high speed steel tools and lubricant, but did not approach the leaded steel in terms of production rate. The steels containing tin did not generally perform better than the 11 SMn30 steel. The 11 SMn30Bi steel gave performance approaching that of the leaded steel in tests with high speed steel tools and lubricant. However, the cost of this addition may make it uneconomic for large scale use.